US20160003325A1 - Driving device - Google Patents
Driving device Download PDFInfo
- Publication number
- US20160003325A1 US20160003325A1 US14/772,601 US201414772601A US2016003325A1 US 20160003325 A1 US20160003325 A1 US 20160003325A1 US 201414772601 A US201414772601 A US 201414772601A US 2016003325 A1 US2016003325 A1 US 2016003325A1
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- United States
- Prior art keywords
- rotation axis
- eccentric body
- case
- gear
- external gear
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H1/00—Toothed gearings for conveying rotary motion
- F16H1/28—Toothed gearings for conveying rotary motion with gears having orbital motion
- F16H1/32—Toothed gearings for conveying rotary motion with gears having orbital motion in which the central axis of the gearing lies inside the periphery of an orbital gear
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H57/00—General details of gearing
- F16H57/02—Gearboxes; Mounting gearing therein
- F16H57/021—Shaft support structures, e.g. partition walls, bearing eyes, casing walls or covers with bearings
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H1/00—Toothed gearings for conveying rotary motion
- F16H1/28—Toothed gearings for conveying rotary motion with gears having orbital motion
- F16H1/32—Toothed gearings for conveying rotary motion with gears having orbital motion in which the central axis of the gearing lies inside the periphery of an orbital gear
- F16H2001/325—Toothed gearings for conveying rotary motion with gears having orbital motion in which the central axis of the gearing lies inside the periphery of an orbital gear comprising a carrier with pins guiding at least one orbital gear with circular holes
Definitions
- the present specification discloses a technique related to a driving device.
- the present specification discloses a technique related to a driving device which rotates a rotated member while doubly supporting the rotated member at its both ends.
- a driving device in which rotates a rotated member while doubly supporting the rotated member at its both ends.
- An example of this type of driving device is disclosed in Japanese Utility Model Application Publication No. H01-175135 (called Patent Document 1 below).
- the driving device of Patent Document 1 is provided with a first frame extending in one direction along a rotation axis of the rotated member, and a second frame extending in another direction along the rotation axis.
- a supporting member for rotatably supporting the rotated member is fixed to each of the first frame and the second frame.
- Each supporting member includes a case, and a shaft supported rotatably by the case.
- the case is fixed to the frame (the first frame, the second frame), and the shaft is fixed to the rotated member.
- a pair of bearings is disposed between the case and the shaft.
- the driving device taught in the present specification rotates a rotated member while doubly supporting the rotated member at its both ends.
- the driving device comprises a fixing member, a first supporting member and a second supporting member.
- the fixing member comprises a first frame extending in one direction along a rotation axis of a rotated member, and a second frame extending in another direction along the rotation axis of the rotated member.
- the first supporting member is attached to the first frame.
- the first supporting member is disposed between the first frame and the rotated member.
- the first supporting member comprises a first case, a first supporting shaft, and a first bearing.
- the first case is provided with a first through hole, and is fixed to one of the first frame and the rotated member.
- the first supporting shaft passes through the first through hole, and is fixed to the other of the first frame and the rotated member.
- the first bearing is disposed between the first case and the first supporting shaft.
- the second supporting member is attached to the second frame.
- the second supporting member is disposed between the second frame and the rotated member.
- the second supporting member comprises a second case, a second supporting shaft, and a second bearing.
- the second case is provided with a second through hole, and is fixed to one of the second frame and the rotated member.
- the second supporting shaft passes through the second through hole, and is fixed to the other of the second frame and the rotated member.
- the second bearing is disposed between the second case and the second supporting shaft. In this driving device, only one first bearing is disposed between the first case and the first supporting shaft, and only one second bearing is disposed between the second case and the second supporting shaft.
- the first case may be fixed to the first frame, and the first supporting shaft may be fixed to the rotated member.
- the first case may be fixed to the rotated member, and the first supporting shaft may be fixed to the first frame.
- the second case may be fixed to the second frame, and the second supporting shaft may be fixed to the rotated member.
- the second case may be fixed to the rotated member, and the second supporting shaft may be fixed to the second frame.
- the one first bearing is disposed between the first case and the first supporting shaft, and therefore even if an assembly error occurred when fixing the first supporting member to the rotated member, the relative positions of the first supporting shaft and the first case can change, with the first bearing as a fulcrum.
- the relative positions of the second supporting shaft and the second case can change, with the second bearing as a fulcrum. Consequently, it is possible to suppress excessive force being exerted on the bearings (the first bearing and the second bearing).
- FIG. 1 shows a cross-sectional view of a state in which a fixed member has been attached to a driving device of a first embodiment
- FIG. 2 shows an enlarged cross-sectional view of a portion surrounded by a broken line II of FIG. 1 ;
- FIG. 3 shows an enlarged cross-sectional view of a portion surrounded by a broken line III of FIG. 2 ;
- FIG. 4 shows a cross-sectional view of a state in which a fixed member has been attached to a driving device of a second embodiment
- FIG. 5 shows an enlarged cross-sectional view of a portion surrounded by a broken line V of FIG. 4 ;
- FIG. 6 shows an enlarged cross-sectional view of a portion surrounded by a broken line VI of FIG. 5 ;
- FIG. 7 shows a cross-sectional view of a state in which a fixed member has been attached to a driving device of a third embodiment
- FIG. 8 shows an enlarged cross-sectional view of a portion surrounded by a broken line VIII of FIG. 7 ;
- FIG. 9 shows an enlarged cross-sectional view of a portion surrounded by a broken line IX of FIG. 8 .
- the first supporting member may comprise a reduction gear structure of the type in which a first external gear rotates eccentrically relative to a first internal gear.
- An example of this type of reduction gear structure is a reduction gear comprising a crankshaft, an eccentric rotary gear, and a rotation gear,
- the crankshaft extends along a rotation axis of an output unit of the reduction gear, and may comprise an eccentric body.
- the eccentric rotary gear engages with the eccentric body, and may rotate eccentrically with the rotation of the crankshaft.
- the rotation gear meshes with the eccentric rotary gear, and may have a number of teeth different from a number of teeth of the eccentric rotary gear.
- the rotation gear may be disposed coaxially with the rotation axis of the output unit of the reduction gear.
- the first crankshaft may be supported by the first supporting shaft.
- the first eccentric body may be provided on the first crankshaft.
- the first internal gear may be provided at a wall surface of a first through hole of a first case.
- the first external gear may engage with the first eccentric body, and may mesh with the first internal gear.
- a second supporting member may comprise a reduction gear structure of the type in which a second external gear rotates eccentrically relative to a second internal gear.
- the second supporting member may comprise a reduction gear structure comprising a second external gear, a second internal gear, and a second crankshaft.
- the second crankshaft may be supported by a second supporting shaft.
- the second eccentric body may be provided on the second crankshaft.
- the second internal gear may be provided at a wall surface of a second through hole of a second case. The second external gear may engage with the second eccentric body, and may mesh with the second internal gear.
- each of the first crankshaft and the second crankshaft may comprise two or more eccentric bodies.
- a third eccentric body which is symmetrically offset from the first eccentric body with respect to a first rotation axis of the first crankshaft may be provided on a first frame side than the first eccentric body of the first crankshaft.
- the third external gear may engage with the third eccentric body.
- a fourth eccentric body which is symmetrically offset from the second eccentric body with respect to a second rotation axis of the second crankshaft may be provided on a second frame side than the second eccentric body of the second crankshaft.
- the fourth external gear may engage with the fourth eccentric body.
- the first external gear and the second external gear may be offset in the same direction with respect to the rotation axis of the rotated member.
- the first rotation axis and the second rotation axis may be coaxial, and the first eccentric body and the second eccentric body may be eccentric in the same direction with respect to the first rotation axis.
- the first supporting member and the second supporting member may comprise only one external gear. That is, the first external gear may be the only external gear provided to the first supporting member, and the second external gear may be the only external gear provided to the second supporting member.
- the first external gear and the second external gear may be symmetrically offset with respect to the rotation axis of the rotated member.
- first rotation axis of the first crankshaft and the second rotation axis of the second crankshaft may be coaxial, and the first eccentric body and the second eccentric body may be symmetrically offset with respect to the first rotation axis.
- the first supporting shaft may be fixed to the first frame
- the first case and the second case may be fixed to the rotated member
- the second supporting shaft may be fixed to the second frame
- FIG. 1 shows a state in which a machine tool 120 has been attached to a driving device 100 .
- the machine tool 120 is an example of a rotated member.
- the driving device 100 is fixed to an output member 110 which rotates relative to a base shaft 104 .
- An entirety of the driving device 100 rotates about a rotation axis 106 relative to the base shaft 104 .
- the driving device 100 rotates the machine tool 120 about a rotation axis 160 .
- the machine tool 120 comprises a body 122 , and a head unit 124 which rotates relative to the body 122 .
- a tool (not shown) is attached to the head unit 124 .
- the driving device 100 comprises a fixing member 102 , a first reduction gear 30 a, and a second reduction gear 30 b.
- the fixing member 102 performs a position fixing of the machine tool 120 in the rotation axis 106 direction.
- the fixing member 102 comprises a first frame 102 a, a second frame 102 b, and a coupling frame 102 c.
- the first frame 102 a extends in one direction along the rotation axis 160 of the machine tool 120 .
- the second frame 102 b extends in the other direction along the rotation axis 160 of the machine tool 120 . That is, the second frame 102 b extends in the opposite direction to the first frame 102 a relative to the machine tool 120 .
- the coupling frame 102 c couples the first frame 102 a and the second frame 102 b, and is fixed to the output member 110 .
- the machine tool 120 is disposed between the first frame 102 a and the second frame 102 b.
- the first reduction gear 30 a is fixed to the first frame 102 a
- the second reduction gear 30 b is fixed to the second frame 102 b.
- the first reduction gear 30 a is an example of a first supporting member
- the second reduction gear 30 b is an example of a second supporting member.
- the first reduction gear 30 a is disposed between the first frame 102 a and the machine tool 120 .
- the first reduction gear 30 a comprises a first case 62 a and a first supporting shaft 56 a.
- the first supporting shaft 56 a is supported rotatably by the first case 62 a.
- the first case 62 a is fixed to the body 122 of the machine tool 120
- the first supporting shaft 56 a is fixed to the first frame 102 a.
- the second reduction gear 30 b is disposed between the second frame 102 b and the machine tool 120 .
- the second reduction gear 30 b comprises a second case 62 b and a second supporting shaft 56 b.
- the second case 62 b is fixed to the body 122 of the machine tool 120 , and the second supporting shaft 56 b is fixed to the second frame 102 b.
- the second supporting shaft 56 b is supported rotatably by the second case 62 b.
- the rotation axis 160 corresponds to a rotation axis of output units (the cases 62 a, 62 b ) of the first reduction gear 30 a and the second reduction gear 30 b. Consequently, the machine tool 120 rotates about the rotation axis 160 with respect to the fixing member 102 .
- a first motor case 132 a is fixed to the first frame 102 a.
- a motor (not shown) for driving the first reduction gear 30 a is housed within the first motor case 132 a.
- a first cover 133 a is fixed to the first frame 102 a. The first cover 133 a prevents the first motor case 132 a from being exposed to the exterior of the driving device 100 .
- a second motor case 132 b is fixed to the second frame 102 b.
- a motor for driving the second reduction gear 30 b is housed within the second motor case 132 b.
- a second cover 133 b is fixed to the second frame 102 b. The second cover 133 b prevents the second motor case 132 b from being exposed to the exterior of the driving device 100 .
- the driving device 100 will be described in detail with reference to FIG. 2 , Moreover, the first reduction gear 30 a and the second reduction gear 30 b comprise substantially identical configurations. Below, the first reduction gear 30 a will be described in detail. Components of the second reduction gear 30 b will be denoted by same reference numbers as in the first reduction gear 30 a , or by reference numbers having the same lower two digits, and a description thereof may be omitted.
- the first case 62 a is fixed to the body 122 of the machine tool 120 via a first connecting member 140 a.
- the first case 62 a comprises a first through hole 58 a.
- the first supporting shaft 56 a passes through the first through hole 58 a.
- the first supporting shaft 56 a is fixed to the first frame 102 a (the fixing member 102 ) via the first motor case 132 a.
- a first bearing 64 a is disposed between the first case 62 a and the first supporting shaft 56 a.
- the first bearing 64 a is an angular contact ball bearing.
- the first reduction gear 30 a comprises a first internal gear 6 a, the first supporting shaft 56 a, a first crankshaft 12 a, and two external gears (first external gear 8 a, third external gear 4 a ).
- the first internal gear 6 a is provided at a wall surface of the first through hole 58 a of the first case 62 a.
- the rotation axis 160 corresponds to rotation axes of the first internal gear 6 a and the first supporting shaft 56 a.
- the first crankshaft 12 a is supported by the first supporting shaft 56 a.
- a rotation axis 20 a is a rotation axis of the first crankshaft 12 a (may be called first rotation axis 20 a below).
- the first rotation axis 20 a is parallel to the rotation axis 160 . That is, the first crankshaft 12 a extends parallel to the rotation axis 160 at a position offset from the rotation axis 160 . Moreover, the first reduction gear 30 a comprises three first crankshafts 12 a. Each of the first crankshafts 12 a is disposed to be equally spaced from each other around the rotation axis 160 .
- Each first crankshaft 12 a comprises two eccentric bodies (first eccentric body 10 a, third eccentric body 2 a ).
- first eccentric body 10 a In a first rotation axis 20 a direction, the first eccentric body 10 a is disposed on the machine tool 120 side than the third eccentric body 2 a.
- the first eccentric body 10 a and the third eccentric body 2 a are eccentric symmetrically with respect to the first rotation axis 20 a.
- the first external gear 8 a engages with the first eccentric body 10 a
- the third external gear 4 a engages with the third eccentric body 2 a.
- the first external gear 8 a In the rotation axis 160 direction, the first external gear 8 a is disposed on the machine tool 120 side than the third external gear 4 a.
- a number of teeth of the first external gear 8 a and that of the third external gear 4 a is identical.
- the first bearing 64 a is disposed on the first motor case 132 a side (the first frame 102 a side) than the first external gear 8 a and the third external gear 4 a. Only one first bearing 64 a is disposed between the first case 62 a and the first supporting shaft 56 a.
- the second case 62 b is fixed to the body 122 of the machine tool 120 via a second connecting member 140 b.
- the second case 62 b comprises a second through hole 58 b.
- the second supporting shaft 56 b passes through the second through hole 58 b.
- the second supporting shaft 56 b is fixed to the second frame 102 b via the second motor case 132 b,
- a second bearing 64 b is disposed between the second case 62 b and the second supporting shaft 56 b.
- the second bearing 64 b is an angular contact ball bearing.
- the second reduction gear 30 b comprises a second internal gear 6 b, the second supporting shaft 56 b, second crankshafts 12 b and two external gears (second external gear 8 b, fourth external gear 4 b ).
- the rotation axis 160 also corresponds to rotation axes of the second internal gear 6 b and the second supporting shaft 56 b.
- a rotation axis 20 b is a rotation axis of each second crankshaft 12 b (may be called second rotation axis 20 b below).
- the second rotation axis 20 b is coaxial with the first rotation axis 20 a. That is, each second crankshaft 12 b is coaxial with the first crankshaft 12 a.
- Each second crankshaft 12 b also extends parallel to the rotation axis 160 .
- Each second crankshaft 12 b comprises two eccentric bodies (second eccentric body 10 b , fourth eccentric body 2 b ).
- the second eccentric body 10 b is disposed on the machine tool 120 side than the fourth eccentric body 2 b.
- the second eccentric body 10 b and the fourth eccentric body 2 b are offset symmetrically with respect to the second rotation axis 20 b.
- the second external gear 8 b engages with the second eccentric body 10 b
- the fourth external gear 4 b engages with the fourth eccentric body 2 b.
- the second external gear 8 b is disposed on the machine tool 120 side than the fourth external gear 4 b.
- the second bearing 64 b is disposed on the second motor case 132 a side (the second frame 102 b side) than the second external gear 8 b and the fourth external gear 4 b, Only one second bearing 64 b is disposed between the second case 62 b and the second supporting shaft 56 b ,
- the configuration of the first reduction gear 30 a will be described in more detail with reference to FIG. 3 .
- the first reduction gear 30 a and the second reduction gear 30 b comprise substantially identical configurations. Consequently, only the configuration of the first reduction gear 30 a will be described, and a description of the configuration of the second reduction gear 30 b will be omitted.
- the first internal gear 6 a is structured by aligning inner teeth pins 5 a along a circumferential direction on a wall surface of the first through hole 58 a. In the rotation axis 160 direction, the first internal gear 6 a is provided at a center of the first case 62 a.
- the first supporting shaft 56 a comprises a first plate 50 a and a second plate 54 a.
- the second plate 54 a comprises a columnar portion 52 a.
- the columnar portion 52 a extends toward the first plate 50 a from the second plate 54 a.
- the columnar portion 52 a is fixed to the first plate 50 a.
- the first plate 50 a is positioned at the machine tool 120 side, and the second plate 54 a is positioned at the motor case 132 a side (the first frame 102 a side).
- the first bearing 64 a is disposed between the second plate 54 a and the first case 62 a.
- a bearing is not disposed between the first plate 50 a and the first case 62 a. That is, the first supporting shaft 56 a is supported by the first case 62 a via the one first bearing 64 a at a position away from the machine tool 120 .
- Each first crankshaft 12 a is supported by the first supporting shaft 56 a via a pair of bearings 14 a.
- the pair of bearings 14 a is tapered roller bearings. Movement of the first crankshaft 12 a in an axial direction and in a radial direction with respect to the first supporting shaft 56 a is regulated by the pair of bearings 14 a.
- the first eccentric body 10 a is positioned at the machine tool 120 side, and the third eccentric body 2 a is positioned at the motor case 132 a side (the first frame 102 a side).
- a first center through hole 34 a, a first supporting shaft through hole 36 a, and a first crankshaft through hole 24 a are provided in the first external gear 8 a.
- a third center through hole 32 a, a third supporting shaft through hole 38 a, and a third crankshaft through hole 26 a are provided in the third external gear 4 a.
- a cylindrical member 28 a passes through the first center through hole 34 a and the third center through hole 32 a.
- the cylindrical member 28 a is fixed to the first plate 50 a and the second plate 54 a.
- the columnar portion 52 a passes through the first supporting shaft through hole 36 a and the third supporting shaft through hole 38 a.
- a clearance is provided between the columnar portion 52 a and the first supporting shaft through hole 36 a, and between the columnar portion 52 a and the third supporting shaft through hole 38 a.
- the first eccentric body 10 a engages with the first crankshaft through hole 24 a via a cylindrical roller bearing 22 a.
- the third eccentric body 2 a engages with the third crankshaft through hole 26 a via a cylindrical roller bearing 18 a.
- An oil seal 40 a is disposed between the first case 62 a and the first plate 50 a, an oil seal 7 a is disposed between the first case 62 a and the second plate 54 a, an oil seal 16 a is disposed between the first plate 52 a and the first crankshaft 12 a, and an oil seal 9 a is disposed between the second plate 54 a and the first crankshaft 12 a.
- Lubricant (oil) within the first reduction gear 30 a is prevented from leaking to the exterior of the first reduction gear 30 a by the oil seals 40 a, 7 a, 16 a and 9 a.
- a motor (not shown) for driving the first reduction gear 30 a is housed within the first motor case 132 a. Torque of the motor is transmitted to the first crankshafts 12 a.
- the first crankshafts 12 a rotate, the first eccentric body 10 a and the third eccentric body 2 a rotate eccentrically around the first rotation axis 20 a.
- the first external gear 8 a and the third external gear 4 a rotate eccentrically with the eccentric rotation of the eccentric bodies 10 a, 2 a while meshing with the first internal gear 6 a.
- An offset directions of the first external gear 8 a and the third external gear 4 a are symmetrical relative to the rotation axis 160 .
- a number of teeth of the first internal gear 6 a and the numbers of teeth of the external gears 8 a, 4 a are different. Consequently, when the external gears 8 a, 4 a rotate eccentrically, the external gears 8 a, 4 a rotate relative to the first internal gear 6 a.
- the external gears 8 a, 4 a can also be called eccentric rotary gears of the first reduction gear 30 a.
- the first internal gear 6 a can also be called a rotation gear of the first reduction gear 30 a,
- the external gears 8 a, 4 a are supported by the first supporting shaft 56 a via the first crankshaft 12 a.
- the first supporting shaft 56 a rotates relative to the first internal gear 6 a.
- the first internal gear 6 a (the first case 62 a ) is fixed to the body 122 of the machine tool 120 via the connecting member 140 a.
- the first supporting shaft 56 a is fixed to the fixing member 102 (the first frame 102 a ) via the first motor case 132 a. Consequently, when the external gears 8 a, 4 a rotate eccentrically, the machine tool 120 rotates around the rotation axis 160 with respect to the fixing member 102 .
- the driving of the first reduction gear 30 a and the driving of the second reduction gear 30 b are performed simultaneously.
- the second reduction gear 30 b also performs the same movement as the first reduction gear 30 a.
- the external gears 8 b, 4 b can also be called eccentric rotary gears of the second reduction gear 30 b.
- the second internal gear 6 b can also be called a rotation gear of the second reduction gear 30 b.
- the driving device 100 supports the machine tool 120 at both ends, and can tilt the position of a tool (not shown) attached to the head unit 124 ,
- the first case 62 a and the second case 62 b are fixed to the machine tool 120 . Further, the first supporting shaft 56 a and the second supporting shaft 56 b are fixed to the fixing member 102 .
- the first case 62 a, the second case 62 b and the machine tool 120 are integrated, and the first supporting shaft 56 a, the second supporting shaft 56 b and the fixing member 102 are integrated.
- the integrated body which is the first case 62 a, the second case 62 b and the machine tool 120 , is supported by the pair of bearings (the first bearing 64 a and the second bearing 64 b ) with respect to the integrated body which is the first supporting shaft 56 a, the second supporting shaft 56 b and the fixing member 102 .
- the machine tool 120 can be supported at both ends with respect to the fixing member 102 . Consequently, it is possible to control the position of the machine tool 120 around the rotation axis 160 with high precision.
- a pair of bearings is disposed between the case and the shaft for each reduction gear. Since the shaft is doubly supported at both ends by the case, the relative position of the shaft and the case in each reduction gear is stable.
- one rotated member e.g., the machine tool
- two reduction gears a force which causes a relative positional shift to occur between the shaft and the case is applied when an assembly error occurs upon attaching the reduction gears to the rotated member.
- a force may be applied to the pair of bearings disposed between the shaft and the case, and a life of the bearings may be reduced.
- the two reduction gears had been required to be attached to the rotated member with high precision.
- first rotation axis 20 a of each first crankshaft 12 a, and the second rotation axis 20 b of each second crankshaft 12 b are coaxial.
- offset directions of the first eccentric body 10 a and the second eccentric body 10 b are the same. Consequently, the movement of the eccentric rotation of the first external gear 8 a, and the movement of the eccentric rotation of the second external gear 8 b is equal at both sides of the machine tool 120 .
- the direction of force applied to the first internal gear 6 a from the first external gear 8 a is equal to the direction of force applied to the second internal gear 6 b from the second external gear 8 b. It is possible to suppress vibration of the machine tool 120 .
- offset directions of the third eccentric body 2 a and the fourth eccentric body 2 b are the same. The movement of the eccentric rotation of the third external gear 4 a, and the movement of the eccentric rotation of the fourth external gear 4 b are equal at both sides of the machine tool 120 .
- the offset direction of the first eccentric body 10 a with respect to the first rotation axis 20 a is symmetrical to the offset direction of the third eccentric body 2 a. Consequently, when driving the first reduction gear 30 a, the positions of the first external gear 8 a and the third external gear 4 a are always symmetrical with respect to the rotation axis 160 . Consequently, it is possible to improve the rotational balance of the first crankshafts 12 a . This characteristic can also be obtained in the second reduction gear 30 b.
- first rotation axis 20 a and the second rotation axis 20 b are coaxial, and the first eccentric body 10 a and the second eccentric body 10 b are eccentric in the same direction with respect to the rotation axes 20 a, 20 b .
- the first rotation axis 20 a and the second rotation axis 20 b may not be coaxial.
- first external gear 8 a of the first reduction gear 30 a and the second external gear 8 b of the second reduction gear 30 b may be offset in the same direction with respect to the rotation axis 160 .
- first crankshafts 12 a and the second crankshafts 12 b are disposed symmetrically with respect to the rotation axis 160 and, when viewed along one direction of the first rotation axis 20 a (or the second rotation axis 20 b ), the offset direction of the first eccentric body 10 a and the offset direction of the second eccentric body 10 b are the same.
- a supporting member not having a reduction gear structure may be used instead of the first reduction gear 30 a and/or the second reduction gear 30 b of the present embodiment.
- only one bearing is disposed between the case and the shaft.
- the machine tool 120 can be caused to rotate about the rotation axis 160 by attaching a motor to the case or the shaft.
- a reduction gear in which an internal gear rotates eccentrically can be used as the first supporting member and/or the second supporting member.
- each of the two supporting members (first supporting member and second supporting member) disposed at both sides of the machine tool 120 is provided with a case and a shaft, and that only one bearing is disposed between the case and the shaft. The same applies in the following embodiments.
- a driving device 200 will be described.
- the driving device 200 is a modification of the driving device 100 .
- the configuration of the supporting member (reduction gear) is different from that of the driving device 100 . Consequently, members which are the same as the members of driving device 100 will be denoted by the same reference numbers as in the driving device 100 or by reference numbers having the same lower two digits, and a description thereof may thereby be omitted.
- the configuration of a first reduction gear 230 a is described, and a description of the configuration of a second reduction gear 230 b may be omitted.
- first eccentric body 210 a is provided on a first crankshaft 212 a of the first reduction gear 230 a.
- second eccentric body 210 b is provided on a second crankshaft 212 b of the second reduction gear 230 b.
- a first rotation axis 220 a of the first crankshaft 212 a and a second rotation axis 220 b of the second crankshaft 212 b are coaxial. Viewed along one direction along the first rotation axis 220 a, an offset direction of the first eccentric body 210 a, and an offset direction of the second eccentric body 210 b are symmetrical with respect to the first rotation axis 220 a.
- a center of the first eccentric body 210 a and a center of the second eccentric body 210 b are symmetrical with respect to the first rotation axis 220 a.
- a first external gear 208 a is engaged with the first eccentric body 210 a
- a second external gear 208 b is engaged with the second eccentric body 210 b. Consequently, when viewed along one direction of a rotation axis 260 , the first external gear 208 a and the second external gear 208 b are eccentric in opposite directions (are symmetrical with respect to the rotation axis 260 ).
- a first bearing 264 a is disposed between a first plate 250 a and a first case 262 a.
- a bearing is not disposed between a second plate 254 a and the first case 262 a.
- a first supporting shaft 256 a is supported by the first case 262 a via the one first bearing 264 a on the machine tool 120 side than the first external gear 208 a.
- the first bearing 264 a is disposed on the machine tool 120 side than the first external gear 208 a.
- a second supporting shaft 256 b is supported by a second case 262 b via one second bearing 264 b on the machine tool 120 side than the second external gear 208 b. That is, in the rotation axis 260 direction, the second bearing 264 b is disposed on the machine tool 120 side than the second external gear 208 b.
- each of the first reduction gear 230 a and the second reduction gear 230 b is provided with only one external gear (the first external gear 208 a, the second external gear 208 b ). Consequently, compared with a reduction gear (e.g., the reduction gears 30 a, 30 b of embodiment 1 ) provided with a plurality of external gears, it is possible to reduce the length in the axial direction of the reduction gears. That is, according to the technique disclosed in the present embodiment, it is possible to realize a compact driving device.
- a reduction gear e.g., the reduction gears 30 a, 30 b of embodiment 1
- first external gear 208 a and the second external gear 208 b are eccentric symmetrically with respect to the rotation axis 260 . Consequently, the force is balanced which is applied from the two external gears (the first external gear 208 a, the second external gear 208 b ) to the integrated body, in which the first case 262 a, the machine tool 120 , and the second case 262 b are combined.
- the first reduction gear 230 a and the second reduction gear 230 b can also be considered as being a reduction gear provided with two external gears, of which part is divided and disposed at both sides of the machine tool 120 .
- the first reduction gear 30 a comprises the two external gears 8 a, 4 a which are eccentric symmetrically with respect to the rotation axis 160 .
- the driving device 200 of the present embodiment can be considered as a structure in which the two external gears 8 a, 4 a of the driving device 100 of the first embodiment are divided, and one of the external gears has been disposed on the opposite side of the machine tool 120 .
- the first bearing 264 a and the second bearing 264 b are each disposed further to the machine tool 120 side than the first external gear 208 a and the second external gear 208 b. That is, the first external gear 208 a and the second external gear 208 b are disposed outside a range where the pair of bearings (the first bearing 264 a, the second bearing 264 b ) support the integrated body which is the cases 262 a, 262 b and the machine tool 120 . Consequently, the machine tool 120 can suppress vibration caused by force being applied to the cases 262 a, 262 b from the external gears 208 a , 208 b.
- first rotation axis 220 a and the second rotation axis 220 b are coaxial, and the first eccentric body 210 a and the second eccentric body 210 b are eccentric symmetrically with respect to the first rotation axis 220 a .
- first external gear 208 a and the second external gear 208 b rotate eccentrically in a state of being eccentric in opposite directions relative to the rotation axis 260 .
- the first eccentric body 210 a and the second eccentric body 210 b need not be symmetrically eccentric with respect to the first rotation axis 220 a (the second rotation axis 220 b ).
- the structure may be such that the first crankshaft 212 a and the second crankshaft 212 b are disposed symmetrically with respect to the rotation axis 260 , and the offset direction of the first eccentric body 210 a and the offset direction of the second eccentric body 210 b are opposite when viewed along one direction of the first rotation axis 220 a (or the second rotation axis 220 b ).
- a driving device 300 will be described.
- the driving device 300 is a modification of the driving device 200 .
- the driving device 300 differs from the driving device 200 only in the structure of reduction gears 330 a and 330 b. Consequently, members the same as those of the driving device 200 will be denoted by the same reference numbers as those of the driving device 200 or by reference numbers having the same lower two digits, and a description thereof is thereby omitted.
- the configuration of the first reduction gear 330 a is described, and a description of the configuration of the second reduction gear 330 b may be omitted.
- a first crankshaft 312 a and a second crankshaft 312 b are disposed coaxially with a rotation axis 360 . That is, the crankshafts 312 a, 312 b are disposed on the rotation axis 360 that is an output unit of the first reduction gear 330 a and the second reduction gear 330 b.
- the first crankshaft 312 a is provided with only one first eccentric body 310 a
- the second crankshaft 312 b is provided with only one second eccentric body 31011 Offset directions of the first eccentric body 310 a and of the second eccentric body 310 b are symmetrical with respect to the rotation axis 360 .
- the first reduction gear 330 a comprises first driven crankshafts 370 a .
- the first reduction gear 330 a comprises three first driven crankshafts 370 a.
- the first driven crankshafts 370 a are each disposed equally spaced from each other around the rotation axis 360 .
- Each of the first driven crankshafts 370 a is provided with only one first driven eccentric body 372 a.
- the second reduction gear 330 b comprises second driven crankshafts 37011
- the second reduction gear 330 b comprises three second driven crankshafts 370 b.
- the second driven crankshafts 370 b are each disposed equally spaced from each other around the rotation axis 360 .
- a rotation axis 380 a of each first driven crankshaft 370 a and a rotation axis 380 b of each second driven crankshaft 370 b are coaxial,
- Each of the second driven crankshafts 370 b is provided with only one second driven eccentric body 372 b.
- an offset direction of the first driven eccentric body 372 a and an offset direction of the second driven eccentric body 372 b are opposite with respect to the rotation axis 380 a.
- Torque of a motor (not shown) is not transmitted directly to the first driven crankshafts 370 a and the second driven crankshafts 370 b.
- the first driven crankshafts 370 a and the second driven crankshafts 370 b rotate with the eccentric rotation of external gears 308 a, 308 b. Since each of the first reduction gear 330 a and the second reduction gear 330 b comprises the first driven crankshafts 370 a and the second driven crankshafts 370 b, the first external gear 308 a and the second external gear 308 b rotate smoothly.
- the first crankshaft 312 a is supported by a first supporting shaft 356 a via a pair of bearings 314 a.
- the pair of bearings 314 a is deep groove ball bearings.
- Each first driven crankshaft 370 a is supported by the first supporting shaft 356 a via a pair of bearings 384 a.
- the pair of bearings 384 a is tapered roller bearings. Movement of the first driven crankshafts 370 a in the axial direction and radial direction is regulated by the tapered roller bearings 384 a.
- the first external gear 308 a comprises a crankshaft through hole 324 a, driven crankshaft through holes 386 a, and supporting shaft through holes 336 a.
- the crankshaft through hole 324 a is provided in a center of the first external gear 308 a.
- the driven crankshaft through holes 386 a and the supporting shaft through holes 336 a are provided alternately in the circumferential direction of the first external gear 308 a.
- the first eccentric body 310 a engages with the crankshaft through hole 324 a via a cylindrical roller bearing 322 a.
- the first driven eccentric body 372 a engages with the driven crankshaft through holes 386 a via cylindrical roller bearings 374 a.
- a columnar portion 352 a of the first supporting shaft 356 a passes through the supporting shaft through hole 336 a.
- An oil seal 382 a is disposed between the first driven crankshaft 370 a and a first plate 350 a, and an oil seal 388 a is disposed between the first driven crankshaft 370 a and a second plate 354 a.
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Abstract
A driving device is provided with a first supporting member disposed in one direction along a rotation axis of a rotated member, and a second supporting member disposed in the other direction. The first supporting member is provided with a first case and a first supporting shaft. The first supporting shaft passes through a first through hole of the first case. The second supporting member is provided with a second case and a second supporting shaft. The second supporting shaft passes through a second through hole of the second case. Only one first bearing is disposed between the first case and the first supporting shaft. Only one second bearing is disposed between the second case and the second supporting shaft.
Description
- This application claims priority to Japanese Patent Application No. 2013-047081, filed on Mar. 8, 2013, the contents of which are hereby incorporated by reference into the present application. The present specification discloses a technique related to a driving device. In particular, the present specification discloses a technique related to a driving device which rotates a rotated member while doubly supporting the rotated member at its both ends.
- A driving device is known in which rotates a rotated member while doubly supporting the rotated member at its both ends. An example of this type of driving device is disclosed in Japanese Utility Model Application Publication No. H01-175135 (called Patent Document 1 below). The driving device of Patent Document 1 is provided with a first frame extending in one direction along a rotation axis of the rotated member, and a second frame extending in another direction along the rotation axis. A supporting member for rotatably supporting the rotated member is fixed to each of the first frame and the second frame. Each supporting member includes a case, and a shaft supported rotatably by the case. The case is fixed to the frame (the first frame, the second frame), and the shaft is fixed to the rotated member. A pair of bearings is disposed between the case and the shaft.
- In a case of supporting a shaft rotatably by a case, it is technical common sense to dispose a pair of bearings between the case and the shaft in order to support the shaft stably. Consequently, in Patent Document 1, the pair of bearings is disposed between the case and the shaft in each supporting member. However, in a case where the rotated member is doubly supported at its both ends, an assembly error may occur when fixing the supporting members to the rotated member. When such an assembly error occurs, a force displacing relative positions of the case and the shaft is applied between the case and the shaft. However, since the relative positions of the case and the shaft are fixed when the pair of bearings is disposed between the case and the shaft, an excessive force is exerted on the bearings. Consequently, when the supporting members are to be fixed to both sides of the rotated member, an assembling operation must be performed with high accuracy. The present specification provides a novel driving device which solves the above problem.
- The driving device taught in the present specification rotates a rotated member while doubly supporting the rotated member at its both ends. The driving device comprises a fixing member, a first supporting member and a second supporting member. The fixing member comprises a first frame extending in one direction along a rotation axis of a rotated member, and a second frame extending in another direction along the rotation axis of the rotated member. The first supporting member is attached to the first frame. The first supporting member is disposed between the first frame and the rotated member. The first supporting member comprises a first case, a first supporting shaft, and a first bearing. The first case is provided with a first through hole, and is fixed to one of the first frame and the rotated member. The first supporting shaft passes through the first through hole, and is fixed to the other of the first frame and the rotated member. The first bearing is disposed between the first case and the first supporting shaft. The second supporting member is attached to the second frame. The second supporting member is disposed between the second frame and the rotated member. The second supporting member comprises a second case, a second supporting shaft, and a second bearing. The second case is provided with a second through hole, and is fixed to one of the second frame and the rotated member. The second supporting shaft passes through the second through hole, and is fixed to the other of the second frame and the rotated member. The second bearing is disposed between the second case and the second supporting shaft. In this driving device, only one first bearing is disposed between the first case and the first supporting shaft, and only one second bearing is disposed between the second case and the second supporting shaft.
- In the case of the aforementioned driving device, the first case may be fixed to the first frame, and the first supporting shaft may be fixed to the rotated member. Alternatively, the first case may be fixed to the rotated member, and the first supporting shaft may be fixed to the first frame. Similarly, the second case may be fixed to the second frame, and the second supporting shaft may be fixed to the rotated member. Alternatively, the second case may be fixed to the rotated member, and the second supporting shaft may be fixed to the second frame.
- According to the aforementioned driving device, only the one first bearing is disposed between the first case and the first supporting shaft, and therefore even if an assembly error occurred when fixing the first supporting member to the rotated member, the relative positions of the first supporting shaft and the first case can change, with the first bearing as a fulcrum. Similarly, even if an assembly error occurred when fixing the second supporting member to the rotated member, the relative positions of the second supporting shaft and the second case can change, with the second bearing as a fulcrum. Consequently, it is possible to suppress excessive force being exerted on the bearings (the first bearing and the second bearing). Moreover, when the first supporting member and the second supporting member are attached to the fixed member, a configuration is completed in which both sides of the fixed member are supported by the pair of bearings. Consequently, the rotated member is stably supported by the fixing member of the driving device by the first supporting member and the second supporting member.
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FIG. 1 shows a cross-sectional view of a state in which a fixed member has been attached to a driving device of a first embodiment; -
FIG. 2 shows an enlarged cross-sectional view of a portion surrounded by a broken line II ofFIG. 1 ; -
FIG. 3 shows an enlarged cross-sectional view of a portion surrounded by a broken line III ofFIG. 2 ; -
FIG. 4 shows a cross-sectional view of a state in which a fixed member has been attached to a driving device of a second embodiment; -
FIG. 5 shows an enlarged cross-sectional view of a portion surrounded by a broken line V ofFIG. 4 ; -
FIG. 6 shows an enlarged cross-sectional view of a portion surrounded by a broken line VI ofFIG. 5 ; -
FIG. 7 shows a cross-sectional view of a state in which a fixed member has been attached to a driving device of a third embodiment; -
FIG. 8 shows an enlarged cross-sectional view of a portion surrounded by a broken line VIII ofFIG. 7 ; and -
FIG. 9 shows an enlarged cross-sectional view of a portion surrounded by a broken line IX ofFIG. 8 . - Below, several technical features of the embodiments taught in the present specification will be noted. Moreover, each of the items noted below solely have technical usefulness.
- The first supporting member may comprise a reduction gear structure of the type in which a first external gear rotates eccentrically relative to a first internal gear. An example of this type of reduction gear structure is a reduction gear comprising a crankshaft, an eccentric rotary gear, and a rotation gear, The crankshaft extends along a rotation axis of an output unit of the reduction gear, and may comprise an eccentric body. The eccentric rotary gear engages with the eccentric body, and may rotate eccentrically with the rotation of the crankshaft. The rotation gear meshes with the eccentric rotary gear, and may have a number of teeth different from a number of teeth of the eccentric rotary gear. The rotation gear may be disposed coaxially with the rotation axis of the output unit of the reduction gear.
- In a case where the first supporting member comprises the reduction gear structure comprising the first external gear, the first internal gear, and a first crankshaft, the first crankshaft may be supported by the first supporting shaft. The first eccentric body may be provided on the first crankshaft. Further, the first internal gear may be provided at a wall surface of a first through hole of a first case. The first external gear may engage with the first eccentric body, and may mesh with the first internal gear.
- A second supporting member, like the first supporting member, may comprise a reduction gear structure of the type in which a second external gear rotates eccentrically relative to a second internal gear. Further, the second supporting member may comprise a reduction gear structure comprising a second external gear, a second internal gear, and a second crankshaft. In this reduction gear structure, also, the second crankshaft may be supported by a second supporting shaft. The second eccentric body may be provided on the second crankshaft. Further, the second internal gear may be provided at a wall surface of a second through hole of a second case. The second external gear may engage with the second eccentric body, and may mesh with the second internal gear.
- In a case where both the first supporting member and the second supporting member comprise a reduction gear structure of the type in which the external gear rotates eccentrically relative to the internal gear, each of the first crankshaft and the second crankshaft may comprise two or more eccentric bodies. As an example, a third eccentric body which is symmetrically offset from the first eccentric body with respect to a first rotation axis of the first crankshaft may be provided on a first frame side than the first eccentric body of the first crankshaft. The third external gear may engage with the third eccentric body. Further, a fourth eccentric body which is symmetrically offset from the second eccentric body with respect to a second rotation axis of the second crankshaft may be provided on a second frame side than the second eccentric body of the second crankshaft. The fourth external gear may engage with the fourth eccentric body. When viewed along a rotation axis direction of the rotated member, the first external gear and the second external gear may be offset in the same direction with respect to the rotation axis of the rotated member. Moreover, in a case of this driving device, the first rotation axis and the second rotation axis may be coaxial, and the first eccentric body and the second eccentric body may be eccentric in the same direction with respect to the first rotation axis.
- In the case where both the first supporting member and the second supporting member comprise the reduction gear structure of the type in which the external gear rotates eccentrically relative to the internal gear, the first supporting member and the second supporting member may comprise only one external gear. That is, the first external gear may be the only external gear provided to the first supporting member, and the second external gear may be the only external gear provided to the second supporting member. When viewed along the rotation axis direction of the rotated member, the first external gear and the second external gear may be symmetrically offset with respect to the rotation axis of the rotated member. In the case of this driving device, the first rotation axis of the first crankshaft and the second rotation axis of the second crankshaft may be coaxial, and the first eccentric body and the second eccentric body may be symmetrically offset with respect to the first rotation axis.
- The first supporting shaft may be fixed to the first frame, the first case and the second case may be fixed to the rotated member, and the second supporting shaft may be fixed to the second frame.
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FIG. 1 shows a state in which amachine tool 120 has been attached to adriving device 100. Themachine tool 120 is an example of a rotated member. Thedriving device 100 is fixed to anoutput member 110 which rotates relative to abase shaft 104. An entirety of thedriving device 100 rotates about arotation axis 106 relative to thebase shaft 104. Thedriving device 100 rotates themachine tool 120 about arotation axis 160. Moreover, themachine tool 120 comprises abody 122, and ahead unit 124 which rotates relative to thebody 122. A tool (not shown) is attached to thehead unit 124. - The
driving device 100 comprises a fixingmember 102, afirst reduction gear 30 a, and asecond reduction gear 30 b. The fixingmember 102 performs a position fixing of themachine tool 120 in therotation axis 106 direction. The fixingmember 102 comprises afirst frame 102 a, asecond frame 102 b, and acoupling frame 102 c. Thefirst frame 102 a extends in one direction along therotation axis 160 of themachine tool 120. Thesecond frame 102 b extends in the other direction along therotation axis 160 of themachine tool 120. That is, thesecond frame 102 b extends in the opposite direction to thefirst frame 102 a relative to themachine tool 120. Thecoupling frame 102 c couples thefirst frame 102 a and thesecond frame 102 b, and is fixed to theoutput member 110. Themachine tool 120 is disposed between thefirst frame 102 a and thesecond frame 102 b. Thefirst reduction gear 30 a is fixed to thefirst frame 102 a, and thesecond reduction gear 30 b is fixed to thesecond frame 102 b. Thefirst reduction gear 30 a is an example of a first supporting member, and thesecond reduction gear 30 b is an example of a second supporting member. - The
first reduction gear 30 a is disposed between thefirst frame 102 a and themachine tool 120. Thefirst reduction gear 30 a comprises afirst case 62 a and a first supportingshaft 56 a. The first supportingshaft 56 a is supported rotatably by thefirst case 62 a. Thefirst case 62 a is fixed to thebody 122 of themachine tool 120, and the first supportingshaft 56 a is fixed to thefirst frame 102 a. Thesecond reduction gear 30 b is disposed between thesecond frame 102 b and themachine tool 120. Thesecond reduction gear 30 b comprises asecond case 62 b and a second supportingshaft 56 b. Thesecond case 62 b is fixed to thebody 122 of themachine tool 120, and the second supportingshaft 56 b is fixed to thesecond frame 102 b. The second supportingshaft 56 b is supported rotatably by thesecond case 62 b. Therotation axis 160 corresponds to a rotation axis of output units (thecases first reduction gear 30 a and thesecond reduction gear 30 b. Consequently, themachine tool 120 rotates about therotation axis 160 with respect to the fixingmember 102. - A
first motor case 132 a is fixed to thefirst frame 102 a. A motor (not shown) for driving thefirst reduction gear 30 a is housed within thefirst motor case 132 a. Afirst cover 133 a is fixed to thefirst frame 102 a. Thefirst cover 133 a prevents thefirst motor case 132 a from being exposed to the exterior of thedriving device 100. Asecond motor case 132 b is fixed to thesecond frame 102 b. A motor for driving thesecond reduction gear 30 b is housed within thesecond motor case 132 b. Asecond cover 133 b is fixed to thesecond frame 102 b. Thesecond cover 133 b prevents thesecond motor case 132 b from being exposed to the exterior of thedriving device 100. - The
driving device 100 will be described in detail with reference toFIG. 2 , Moreover, thefirst reduction gear 30 a and thesecond reduction gear 30 b comprise substantially identical configurations. Below, thefirst reduction gear 30 a will be described in detail. Components of thesecond reduction gear 30 b will be denoted by same reference numbers as in thefirst reduction gear 30 a, or by reference numbers having the same lower two digits, and a description thereof may be omitted. - The
first case 62 a is fixed to thebody 122 of themachine tool 120 via a first connectingmember 140 a. Thefirst case 62 a comprises a first throughhole 58 a. The first supportingshaft 56 a passes through the first throughhole 58 a. The first supportingshaft 56 a is fixed to thefirst frame 102 a (the fixing member 102) via thefirst motor case 132 a. Afirst bearing 64 a is disposed between thefirst case 62 a and the first supportingshaft 56 a. Thefirst bearing 64 a is an angular contact ball bearing. - The
first reduction gear 30 a comprises a firstinternal gear 6 a, the first supportingshaft 56 a, afirst crankshaft 12 a, and two external gears (firstexternal gear 8 a, thirdexternal gear 4 a). The firstinternal gear 6 a is provided at a wall surface of the first throughhole 58 a of thefirst case 62 a. Therotation axis 160 corresponds to rotation axes of the firstinternal gear 6 a and the first supportingshaft 56 a. Thefirst crankshaft 12 a is supported by the first supportingshaft 56 a. Arotation axis 20 a is a rotation axis of thefirst crankshaft 12 a (may be calledfirst rotation axis 20 a below). Thefirst rotation axis 20 a is parallel to therotation axis 160. That is, thefirst crankshaft 12 a extends parallel to therotation axis 160 at a position offset from therotation axis 160. Moreover, thefirst reduction gear 30 a comprises threefirst crankshafts 12 a. Each of thefirst crankshafts 12 a is disposed to be equally spaced from each other around therotation axis 160. - Each
first crankshaft 12 a comprises two eccentric bodies (firsteccentric body 10 a, thirdeccentric body 2 a). In afirst rotation axis 20 a direction, the firsteccentric body 10 a is disposed on themachine tool 120 side than the thirdeccentric body 2 a. The firsteccentric body 10 a and the thirdeccentric body 2 a are eccentric symmetrically with respect to thefirst rotation axis 20 a. The firstexternal gear 8 a engages with the firsteccentric body 10 a, and the thirdexternal gear 4 a engages with the thirdeccentric body 2 a. In therotation axis 160 direction, the firstexternal gear 8 a is disposed on themachine tool 120 side than the thirdexternal gear 4 a. A number of teeth of the firstexternal gear 8 a and that of the thirdexternal gear 4 a is identical. In therotation axis 160 direction, thefirst bearing 64 a is disposed on thefirst motor case 132 a side (thefirst frame 102 a side) than the firstexternal gear 8 a and the thirdexternal gear 4 a. Only onefirst bearing 64 a is disposed between thefirst case 62 a and the first supportingshaft 56 a. - The
second case 62 b is fixed to thebody 122 of themachine tool 120 via a second connectingmember 140 b. Thesecond case 62 b comprises a second throughhole 58 b. The second supportingshaft 56 b passes through the second throughhole 58 b. The second supportingshaft 56 b is fixed to thesecond frame 102 b via thesecond motor case 132 b, Asecond bearing 64 b is disposed between thesecond case 62 b and the second supportingshaft 56 b. Thesecond bearing 64 b is an angular contact ball bearing. - The
second reduction gear 30 b comprises a secondinternal gear 6 b, the second supportingshaft 56 b,second crankshafts 12 b and two external gears (secondexternal gear 8 b, fourthexternal gear 4 b). Therotation axis 160 also corresponds to rotation axes of the secondinternal gear 6 b and the second supportingshaft 56 b. Arotation axis 20 b is a rotation axis of eachsecond crankshaft 12 b (may be calledsecond rotation axis 20 b below). Thesecond rotation axis 20 b is coaxial with thefirst rotation axis 20 a. That is, eachsecond crankshaft 12 b is coaxial with thefirst crankshaft 12 a. Eachsecond crankshaft 12 b also extends parallel to therotation axis 160. - Each
second crankshaft 12 b comprises two eccentric bodies (secondeccentric body 10 b, fourtheccentric body 2 b). In thesecond rotation axis 20 b direction, the secondeccentric body 10 b is disposed on themachine tool 120 side than the fourtheccentric body 2 b. The secondeccentric body 10 b and the fourtheccentric body 2 b are offset symmetrically with respect to thesecond rotation axis 20 b. The secondexternal gear 8 b engages with the secondeccentric body 10 b, and the fourthexternal gear 4 b engages with the fourtheccentric body 2 b. In therotation axis 160 direction, the secondexternal gear 8 b is disposed on themachine tool 120 side than the fourthexternal gear 4 b. In therotation axis 160 direction, thesecond bearing 64 b is disposed on thesecond motor case 132 a side (thesecond frame 102 b side) than the secondexternal gear 8 b and the fourthexternal gear 4 b, Only onesecond bearing 64 b is disposed between thesecond case 62 b and the second supportingshaft 56 b, - The configuration of the
first reduction gear 30 a will be described in more detail with reference toFIG. 3 . As described above, thefirst reduction gear 30 a and thesecond reduction gear 30 b comprise substantially identical configurations. Consequently, only the configuration of thefirst reduction gear 30 a will be described, and a description of the configuration of thesecond reduction gear 30 b will be omitted. - The first
internal gear 6 a is structured by aligning inner teeth pins 5 a along a circumferential direction on a wall surface of the first throughhole 58 a. In therotation axis 160 direction, the firstinternal gear 6 a is provided at a center of thefirst case 62 a. The first supportingshaft 56 a comprises afirst plate 50 a and asecond plate 54 a. Thesecond plate 54 a comprises acolumnar portion 52 a. Thecolumnar portion 52 a extends toward thefirst plate 50 a from thesecond plate 54 a. Thecolumnar portion 52 a is fixed to thefirst plate 50 a. In therotation axis 160 direction, thefirst plate 50 a is positioned at themachine tool 120 side, and thesecond plate 54 a is positioned at themotor case 132 a side (thefirst frame 102 a side). Thefirst bearing 64 a is disposed between thesecond plate 54 a and thefirst case 62 a. A bearing is not disposed between thefirst plate 50 a and thefirst case 62 a. That is, the first supportingshaft 56 a is supported by thefirst case 62 a via the onefirst bearing 64 a at a position away from themachine tool 120. - Each
first crankshaft 12 a is supported by the first supportingshaft 56 a via a pair ofbearings 14 a. The pair ofbearings 14 a is tapered roller bearings. Movement of thefirst crankshaft 12 a in an axial direction and in a radial direction with respect to the first supportingshaft 56 a is regulated by the pair ofbearings 14 a. The firsteccentric body 10 a is positioned at themachine tool 120 side, and the thirdeccentric body 2 a is positioned at themotor case 132 a side (thefirst frame 102 a side). - A first center through
hole 34 a, a first supporting shaft throughhole 36 a, and a first crankshaft throughhole 24 a are provided in the firstexternal gear 8 a. A third center throughhole 32 a, a third supporting shaft throughhole 38 a, and a third crankshaft throughhole 26 a are provided in the thirdexternal gear 4 a. Acylindrical member 28 a passes through the first center throughhole 34 a and the third center throughhole 32 a. Thecylindrical member 28 a is fixed to thefirst plate 50 a and thesecond plate 54 a. Thecolumnar portion 52 a passes through the first supporting shaft throughhole 36 a and the third supporting shaft throughhole 38 a. A clearance is provided between thecolumnar portion 52 a and the first supporting shaft throughhole 36 a, and between thecolumnar portion 52 a and the third supporting shaft throughhole 38 a. The firsteccentric body 10 a engages with the first crankshaft throughhole 24 a via acylindrical roller bearing 22 a. The thirdeccentric body 2 a engages with the third crankshaft throughhole 26 a via acylindrical roller bearing 18 a. - An
oil seal 40 a is disposed between thefirst case 62 a and thefirst plate 50 a, anoil seal 7 a is disposed between thefirst case 62 a and thesecond plate 54 a, anoil seal 16 a is disposed between thefirst plate 52 a and thefirst crankshaft 12 a, and anoil seal 9 a is disposed between thesecond plate 54 a and thefirst crankshaft 12 a. Lubricant (oil) within thefirst reduction gear 30 a is prevented from leaking to the exterior of thefirst reduction gear 30 a by the oil seals 40 a, 7 a, 16 a and 9 a. - A motor (not shown) for driving the
first reduction gear 30 a is housed within thefirst motor case 132 a. Torque of the motor is transmitted to thefirst crankshafts 12 a. When thefirst crankshafts 12 a rotate, the firsteccentric body 10 a and the thirdeccentric body 2 a rotate eccentrically around thefirst rotation axis 20 a. The firstexternal gear 8 a and the thirdexternal gear 4 a rotate eccentrically with the eccentric rotation of theeccentric bodies internal gear 6 a. An offset directions of the firstexternal gear 8 a and the thirdexternal gear 4 a are symmetrical relative to therotation axis 160. - A number of teeth of the first
internal gear 6 a and the numbers of teeth of theexternal gears external gears external gears internal gear 6 a. Theexternal gears first reduction gear 30 a. The firstinternal gear 6 a can also be called a rotation gear of thefirst reduction gear 30 a, Theexternal gears shaft 56 a via thefirst crankshaft 12 a. Therefore, when theexternal gears shaft 56 a rotates relative to the firstinternal gear 6 a. The firstinternal gear 6 a (thefirst case 62 a) is fixed to thebody 122 of themachine tool 120 via the connectingmember 140 a. Further, the first supportingshaft 56 a is fixed to the fixing member 102 (thefirst frame 102 a) via thefirst motor case 132 a. Consequently, when theexternal gears machine tool 120 rotates around therotation axis 160 with respect to the fixingmember 102. The driving of thefirst reduction gear 30 a and the driving of thesecond reduction gear 30 b are performed simultaneously. Consequently, thesecond reduction gear 30 b also performs the same movement as thefirst reduction gear 30 a. Moreover, theexternal gears second reduction gear 30 b. The secondinternal gear 6 b can also be called a rotation gear of thesecond reduction gear 30 b. Thedriving device 100 supports themachine tool 120 at both ends, and can tilt the position of a tool (not shown) attached to thehead unit 124, - The characteristics of the
driving device 100 will be described. As described above, thefirst case 62 a and thesecond case 62 b are fixed to themachine tool 120. Further, the first supportingshaft 56 a and the second supportingshaft 56 b are fixed to the fixingmember 102. When themachine tool 120 is attached to thedriving device 100, thefirst case 62 a, thesecond case 62 b and themachine tool 120 are integrated, and the first supportingshaft 56 a, the second supportingshaft 56 b and the fixingmember 102 are integrated. The integrated body, which is thefirst case 62 a, thesecond case 62 b and themachine tool 120, is supported by the pair of bearings (thefirst bearing 64 a and thesecond bearing 64 b) with respect to the integrated body which is the first supportingshaft 56 a, the second supportingshaft 56 b and the fixingmember 102. Themachine tool 120 can be supported at both ends with respect to the fixingmember 102. Consequently, it is possible to control the position of themachine tool 120 around therotation axis 160 with high precision. - Moreover, in a conventional driving device, a pair of bearings is disposed between the case and the shaft for each reduction gear. Since the shaft is doubly supported at both ends by the case, the relative position of the shaft and the case in each reduction gear is stable. However, in the case where one rotated member (e.g., the machine tool) is doubly supported at its both ends by two reduction gears, a force which causes a relative positional shift to occur between the shaft and the case is applied when an assembly error occurs upon attaching the reduction gears to the rotated member. As a result, a force may be applied to the pair of bearings disposed between the shaft and the case, and a life of the bearings may be reduced. In order to avoid this type of inconvenience, in the conventional driving device, the two reduction gears had been required to be attached to the rotated member with high precision.
- In the driving device taught in the present specification, only one bearing is disposed between the shaft and the case in each of the reduction gears. Consequently, even if the assembly error occurs upon attaching the two reduction gears to the machine tool, the positions of the shaft and the case can shift relatively. As a result, it is possible to suppress the excessive force being applied to the bearing. That is, in the technique disclosed in the present specification, the shaft is intentionally not supported firmly by the case in each of the reduction gears. Thereby, it is possible to realize a highly durable driving device (having a long life).
- Other characteristics of the
driving device 100 will be described. As described above, thefirst rotation axis 20 a of eachfirst crankshaft 12 a, and thesecond rotation axis 20 b of eachsecond crankshaft 12 b are coaxial. When viewed along one direction of thefirst rotation axis 20 a, offset directions of the firsteccentric body 10 a and the secondeccentric body 10 b are the same. Consequently, the movement of the eccentric rotation of the firstexternal gear 8 a, and the movement of the eccentric rotation of the secondexternal gear 8 b is equal at both sides of themachine tool 120. As a result, when driving thedriving device 100, the direction of force applied to the firstinternal gear 6 a from the firstexternal gear 8 a is equal to the direction of force applied to the secondinternal gear 6 b from the secondexternal gear 8 b. It is possible to suppress vibration of themachine tool 120. Moreover, when viewed along the one direction of thefirst rotation axis 20 a, offset directions of the thirdeccentric body 2 a and the fourtheccentric body 2 b are the same. The movement of the eccentric rotation of the thirdexternal gear 4 a, and the movement of the eccentric rotation of the fourthexternal gear 4 b are equal at both sides of themachine tool 120. - Further, as described above, in the
first reduction gear 30 a, the offset direction of the firsteccentric body 10 a with respect to thefirst rotation axis 20 a is symmetrical to the offset direction of the thirdeccentric body 2 a. Consequently, when driving thefirst reduction gear 30 a, the positions of the firstexternal gear 8 a and the thirdexternal gear 4 a are always symmetrical with respect to therotation axis 160. Consequently, it is possible to improve the rotational balance of thefirst crankshafts 12 a. This characteristic can also be obtained in thesecond reduction gear 30 b. - Moreover, in the present embodiment, a structure was described in which the
first rotation axis 20 a and thesecond rotation axis 20 b are coaxial, and the firsteccentric body 10 a and the secondeccentric body 10 b are eccentric in the same direction with respect to the rotation axes 20 a, 20 b. However, in a structure in which the movement of the eccentric rotation of the firstexternal gear 8 a and the movement of the eccentric rotation of the secondexternal gear 8 b is equal at both sides of themachine tool 120, thefirst rotation axis 20 a and thesecond rotation axis 20 b may not be coaxial. That is, the firstexternal gear 8 a of thefirst reduction gear 30 a and the secondexternal gear 8 b of thesecond reduction gear 30 b may be offset in the same direction with respect to therotation axis 160. For example, a structure is possible in which thefirst crankshafts 12 a and thesecond crankshafts 12 b are disposed symmetrically with respect to therotation axis 160 and, when viewed along one direction of thefirst rotation axis 20 a (or thesecond rotation axis 20 b), the offset direction of the firsteccentric body 10 a and the offset direction of the secondeccentric body 10 b are the same. - Further, in the present embodiment, an example was described using reduction gears as the first supporting member and the second supporting member. However, a supporting member not having a reduction gear structure may be used instead of the
first reduction gear 30 a and/or thesecond reduction gear 30 b of the present embodiment. In this case, also, only one bearing is disposed between the case and the shaft. In the case of using a supporting member not having a reduction gear structure, themachine tool 120 can be caused to rotate about therotation axis 160 by attaching a motor to the case or the shaft. Further, a reduction gear in which an internal gear rotates eccentrically can be used as the first supporting member and/or the second supporting member. The important thing is that each of the two supporting members (first supporting member and second supporting member) disposed at both sides of themachine tool 120 is provided with a case and a shaft, and that only one bearing is disposed between the case and the shaft. The same applies in the following embodiments. - A driving
device 200 will be described. Thedriving device 200 is a modification of thedriving device 100. Specifically, in thedriving device 200, only the configuration of the supporting member (reduction gear) is different from that of thedriving device 100. Consequently, members which are the same as the members of drivingdevice 100 will be denoted by the same reference numbers as in thedriving device 100 or by reference numbers having the same lower two digits, and a description thereof may thereby be omitted. Further, the configuration of afirst reduction gear 230 a is described, and a description of the configuration of asecond reduction gear 230 b may be omitted. - As shown in
FIG. 4 toFIG. 6 , only one firsteccentric body 210 a is provided on afirst crankshaft 212 a of thefirst reduction gear 230 a. Similarly, only one secondeccentric body 210 b is provided on asecond crankshaft 212 b of thesecond reduction gear 230 b. Afirst rotation axis 220 a of thefirst crankshaft 212 a and asecond rotation axis 220 b of thesecond crankshaft 212 b are coaxial. Viewed along one direction along thefirst rotation axis 220 a, an offset direction of the firsteccentric body 210 a, and an offset direction of the secondeccentric body 210 b are symmetrical with respect to thefirst rotation axis 220 a. That is, a center of the firsteccentric body 210 a and a center of the secondeccentric body 210 b are symmetrical with respect to thefirst rotation axis 220 a. A firstexternal gear 208 a is engaged with the firsteccentric body 210 a, and a secondexternal gear 208 b is engaged with the secondeccentric body 210 b. Consequently, when viewed along one direction of arotation axis 260, the firstexternal gear 208 a and the secondexternal gear 208 b are eccentric in opposite directions (are symmetrical with respect to the rotation axis 260). - As shown in
FIG. 5 andFIG. 6 , in thefirst reduction gear 230 a, afirst bearing 264 a is disposed between afirst plate 250 a and afirst case 262 a. A bearing is not disposed between asecond plate 254 a and thefirst case 262 a. A first supportingshaft 256 a is supported by thefirst case 262 a via the onefirst bearing 264 a on themachine tool 120 side than the firstexternal gear 208 a. In other words, in therotation axis 260 direction, thefirst bearing 264 a is disposed on themachine tool 120 side than the firstexternal gear 208 a. - Similarly, in the
second reduction gear 230 b, a second supportingshaft 256 b is supported by asecond case 262 b via onesecond bearing 264 b on themachine tool 120 side than the secondexternal gear 208 b. That is, in therotation axis 260 direction, thesecond bearing 264 b is disposed on themachine tool 120 side than the secondexternal gear 208 b. - The characteristics of the
driving device 200 will be described. As described above, in thedriving device 200, each of thefirst reduction gear 230 a and thesecond reduction gear 230 b is provided with only one external gear (the firstexternal gear 208 a, the secondexternal gear 208 b). Consequently, compared with a reduction gear (e.g., the reduction gears 30 a, 30 b of embodiment 1) provided with a plurality of external gears, it is possible to reduce the length in the axial direction of the reduction gears. That is, according to the technique disclosed in the present embodiment, it is possible to realize a compact driving device. - Further, the first
external gear 208 a and the secondexternal gear 208 b are eccentric symmetrically with respect to therotation axis 260. Consequently, the force is balanced which is applied from the two external gears (the firstexternal gear 208 a, the secondexternal gear 208 b) to the integrated body, in which thefirst case 262 a, themachine tool 120, and thesecond case 262 b are combined. - The
first reduction gear 230 a and thesecond reduction gear 230 b can also be considered as being a reduction gear provided with two external gears, of which part is divided and disposed at both sides of themachine tool 120. For example, in the case of thedriving device 100 of the first embodiment, thefirst reduction gear 30 a comprises the twoexternal gears rotation axis 160. Thedriving device 200 of the present embodiment can be considered as a structure in which the twoexternal gears driving device 100 of the first embodiment are divided, and one of the external gears has been disposed on the opposite side of themachine tool 120. - In the
driving device 200, thefirst bearing 264 a and thesecond bearing 264 b are each disposed further to themachine tool 120 side than the firstexternal gear 208 a and the secondexternal gear 208 b. That is, the firstexternal gear 208 a and the secondexternal gear 208 b are disposed outside a range where the pair of bearings (thefirst bearing 264 a, thesecond bearing 264 b) support the integrated body which is thecases machine tool 120. Consequently, themachine tool 120 can suppress vibration caused by force being applied to thecases external gears - Moreover, in the present embodiment, a structure was described in which the
first rotation axis 220 a and thesecond rotation axis 220 b are coaxial, and the firsteccentric body 210 a and the secondeccentric body 210 b are eccentric symmetrically with respect to thefirst rotation axis 220 a. However, the important thing is that the firstexternal gear 208 a and the secondexternal gear 208 b rotate eccentrically in a state of being eccentric in opposite directions relative to therotation axis 260. With this type of structure, the firsteccentric body 210 a and the secondeccentric body 210 b need not be symmetrically eccentric with respect to thefirst rotation axis 220 a (thesecond rotation axis 220 b). For example, the structure may be such that thefirst crankshaft 212 a and thesecond crankshaft 212 b are disposed symmetrically with respect to therotation axis 260, and the offset direction of the firsteccentric body 210 a and the offset direction of the secondeccentric body 210 b are opposite when viewed along one direction of thefirst rotation axis 220 a (or thesecond rotation axis 220 b). - A driving
device 300 will be described. Thedriving device 300 is a modification of thedriving device 200. Specifically, the drivingdevice 300 differs from the drivingdevice 200 only in the structure of reduction gears 330 a and 330 b. Consequently, members the same as those of thedriving device 200 will be denoted by the same reference numbers as those of thedriving device 200 or by reference numbers having the same lower two digits, and a description thereof is thereby omitted. Further, the configuration of thefirst reduction gear 330 a is described, and a description of the configuration of thesecond reduction gear 330 b may be omitted. - As shown in
FIG. 7 toFIG. 9 , in thedriving device 300, afirst crankshaft 312 a and asecond crankshaft 312 b are disposed coaxially with arotation axis 360. That is, thecrankshafts rotation axis 360 that is an output unit of thefirst reduction gear 330 a and thesecond reduction gear 330 b. Thefirst crankshaft 312 a is provided with only one firsteccentric body 310 a, and thesecond crankshaft 312 b is provided with only one second eccentric body 31011 Offset directions of the firsteccentric body 310 a and of the secondeccentric body 310 b are symmetrical with respect to therotation axis 360. - As shown in
FIG. 8 , thefirst reduction gear 330 a comprises first drivencrankshafts 370 a. Thefirst reduction gear 330 a comprises three first drivencrankshafts 370 a. The first drivencrankshafts 370 a are each disposed equally spaced from each other around therotation axis 360. Each of the first drivencrankshafts 370 a is provided with only one first driveneccentric body 372 a. Thesecond reduction gear 330 b comprises second driven crankshafts 37011 Thesecond reduction gear 330 b comprises three second drivencrankshafts 370 b. The second drivencrankshafts 370 b are each disposed equally spaced from each other around therotation axis 360. Arotation axis 380 a of each first drivencrankshaft 370 a and arotation axis 380 b of each second drivencrankshaft 370 b are coaxial, - Each of the second driven
crankshafts 370 b is provided with only one second driveneccentric body 372 b. When viewed along one direction of therotation axis 380 a, an offset direction of the first driveneccentric body 372 a and an offset direction of the second driveneccentric body 372 b are opposite with respect to therotation axis 380 a. - Torque of a motor (not shown) is not transmitted directly to the first driven
crankshafts 370 a and the second drivencrankshafts 370 b. The first drivencrankshafts 370 a and the second drivencrankshafts 370 b rotate with the eccentric rotation ofexternal gears first reduction gear 330 a and thesecond reduction gear 330 b comprises the first drivencrankshafts 370 a and the second drivencrankshafts 370 b, the firstexternal gear 308 a and the secondexternal gear 308 b rotate smoothly. - As shown in
FIG. 9 , thefirst crankshaft 312 a is supported by a first supportingshaft 356 a via a pair ofbearings 314 a. The pair ofbearings 314 a is deep groove ball bearings. Each first drivencrankshaft 370 a is supported by the first supportingshaft 356 a via a pair ofbearings 384 a. The pair ofbearings 384 a is tapered roller bearings. Movement of the first drivencrankshafts 370 a in the axial direction and radial direction is regulated by the taperedroller bearings 384 a. - The first
external gear 308 a comprises a crankshaft throughhole 324 a, driven crankshaft throughholes 386 a, and supporting shaft throughholes 336 a. The crankshaft throughhole 324 a is provided in a center of the firstexternal gear 308 a. The driven crankshaft throughholes 386 a and the supporting shaft throughholes 336 a are provided alternately in the circumferential direction of the firstexternal gear 308 a. The firsteccentric body 310 a engages with the crankshaft throughhole 324 a via a cylindrical roller bearing 322 a. The first driveneccentric body 372 a engages with the driven crankshaft throughholes 386 a via cylindrical roller bearings 374 a. Acolumnar portion 352 a of the first supportingshaft 356 a passes through the supporting shaft throughhole 336 a. Anoil seal 382 a is disposed between the first drivencrankshaft 370 a and afirst plate 350 a, and anoil seal 388 a is disposed between the first drivencrankshaft 370 a and asecond plate 354 a. - Specific examples of the present invention have been described in detail, however, these are mere exemplary indications and thus do not limit the scope of the claims. The art described in the claims includes modifications and variations of the specific examples presented above. Technical features described in the description and the drawings may technically be useful alone or in various combinations, and are not limited to the combinations as originally claimed. Further, the art described in the description and the drawings may concurrently achieve a plurality of aims, and technical significance thereof resides in achieving any one of such aims.
Claims (9)
1. A driving device comprising:
a fixing member comprising a first frame extending in one direction along a rotation axis of a rotated member, and a second frame extending in another direction along the rotation axis of the rotated member;
a first supporting member attached to the first frame, and disposed between the first frame and the rotated member;
a second supporting member attached to the second frame, and disposed between the second frame and the rotated member,
wherein the first supporting member comprises:
a first case provided with a first through hole, and fixed to one of the first frame and the rotated member;
a first supporting shaft passing through the first through hole, and fixed to the other of the first frame and the rotated member; and
a first bearing disposed between the first case and the first supporting shaft,
the second supporting member comprises:
a second case provided with a second through hole, and fixed to one of the second frame and the rotated member;
a second supporting shaft passing through the second through hole, and fixed to the other of the second frame and the rotated member; and
a second bearing disposed between the second case and the second supporting shaft,
only one first bearing is disposed between the first case and the first supporting shaft, and
only one second bearing is disposed between the second case and the second supporting shaft.
2. The driving device according to claim 1 , wherein
the first supporting member comprises a reduction gear structure of a type configured such that a first external gear rotates eccentrically relative to a first internal gear.
3. The driving device according to claim 2 , wherein
the second supporting member comprises a reduction gear structure of a type configured such that a second external gear rotates eccentrically relative to a second internal gear.
4. The driving device according to claim 2 , further comprising:
a first crankshaft supported by the first supporting shaft, and provided with a first eccentric body,
wherein the first internal gear is provided at a wall surface of the first through hole, and
the first external gear engages with the first eccentric body, and meshes with the first internal gear.
5. The driving device according to claim 4 , wherein
the second supporting member comprises a reduction gear structure of a type configured such that a second external gear rotates eccentrically relative to a second internal gear,
the driving device further comprises a second crankshaft supported by the second supporting shaft, and provided with a second eccentric body,
the second internal gear is provided at a wall surface of the second through hole, and
the second external gear engages with the second eccentric body, and meshes with the second internal gear.
6. The driving device according to claim 5 , wherein
a third eccentric body is provided on a first frame side than the first eccentric body of the first crankshaft, and the third eccentric body is symmetrically eccentric with the first eccentric body with respect to a first rotation axis of the first crankshaft,
a third external gear engages with the third eccentric body,
a fourth eccentric body is provided on a second frame side than the second eccentric body of the second crankshaft, and the fourth eccentric body is symmetrically eccentric with the second eccentric body with respect to a second rotation axis of the second crankshaft,
a fourth external gear engages with the fourth eccentric body, and
when viewed along a rotation axis direction of the rotated member, the first external gear and the second external gear are eccentric in a same direction with respect to the rotation axis of the rotated member.
7. The driving device according to claim 6 , wherein
the first rotation axis and the second rotation axis are coaxial, and
the first eccentric body and the second eccentric body are eccentric in the same direction with respect to the first rotation axis.
8. The driving device according to claim 5 , wherein
the first external gear is the only external gear provided to the first supporting member,
the second external gear is the only external gear provided to the second supporting member, and
when viewed along the rotation axis direction of the rotated member, the first external gear and the second external gear are symmetrically eccentric with respect to the rotation axis of the rotated member.
9. The driving device according to claim 8 , wherein
the first rotation axis of the first crankshaft and the second rotation axis of the second crankshaft are coaxial, and
the first eccentric body and the second eccentric body are symmetrically eccentric with respect to the first rotation axis.
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JP2013047081A JP6154162B2 (en) | 2013-03-08 | 2013-03-08 | Drive device |
JP2013-047081 | 2013-03-08 | ||
PCT/JP2014/054750 WO2014136638A1 (en) | 2013-03-08 | 2014-02-26 | Drive device |
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US20160003325A1 true US20160003325A1 (en) | 2016-01-07 |
US9903442B2 US9903442B2 (en) | 2018-02-27 |
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US14/772,601 Active 2034-07-05 US9903442B2 (en) | 2013-03-08 | 2014-02-26 | Driving device |
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US (1) | US9903442B2 (en) |
JP (1) | JP6154162B2 (en) |
KR (1) | KR102194175B1 (en) |
CN (1) | CN105008764B (en) |
DE (1) | DE112014001191B4 (en) |
TW (1) | TWI647059B (en) |
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US8794883B2 (en) * | 2010-07-20 | 2014-08-05 | Industrial Technology Research Institute | Rotary spindle head with gear reducer |
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JP2003048135A (en) * | 2001-08-07 | 2003-02-18 | Colombo Mauro | Operation head |
JP2004338007A (en) * | 2003-05-14 | 2004-12-02 | Mitsubishi Heavy Ind Ltd | Rotary drive mechanism, table device, tool spindle device, and machine tool |
WO2009057526A1 (en) * | 2007-10-31 | 2009-05-07 | Nabtesco Corporation | Speed reducer |
JP2009250279A (en) * | 2008-04-02 | 2009-10-29 | Sumitomo Heavy Ind Ltd | Reduction device |
EP2354594B1 (en) | 2008-11-05 | 2013-05-29 | Nabtesco Corporation | Power transmitting gear device |
TWM428282U (en) * | 2009-06-04 | 2012-05-01 | Regal Machinery Co Ltd | Decelerator with axial device capable of withstanding eccentric oscillations of output shaft |
JP2011064273A (en) * | 2009-09-17 | 2011-03-31 | Nabtesco Corp | Eccentric reduction gear |
JP5496323B2 (en) * | 2010-04-23 | 2014-05-21 | 株式会社牧野フライス製作所 | Spindle unit and table unit, and machine tool |
JP5654798B2 (en) * | 2010-07-30 | 2015-01-14 | 住友重機械工業株式会社 | Roller retainer and swinging intermeshing gear device |
JP5291685B2 (en) * | 2010-09-21 | 2013-09-18 | 住友重機械工業株式会社 | Eccentric oscillating gear unit |
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2013
- 2013-03-08 JP JP2013047081A patent/JP6154162B2/en active Active
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2014
- 2014-02-26 KR KR1020157027465A patent/KR102194175B1/en active IP Right Grant
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- 2014-02-26 WO PCT/JP2014/054750 patent/WO2014136638A1/en active Application Filing
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US20100310335A1 (en) * | 2006-09-14 | 2010-12-09 | Tsudakoma Kogyo Kabushiki Kaisha | Working head for machine tool |
US20100206599A1 (en) * | 2007-10-11 | 2010-08-19 | Akira Sugiyama | Machine-tool spindle head |
US8794883B2 (en) * | 2010-07-20 | 2014-08-05 | Industrial Technology Research Institute | Rotary spindle head with gear reducer |
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KR20150128811A (en) | 2015-11-18 |
DE112014001191B4 (en) | 2022-11-03 |
TWI647059B (en) | 2019-01-11 |
CN105008764A (en) | 2015-10-28 |
DE112014001191T5 (en) | 2015-11-26 |
KR102194175B1 (en) | 2020-12-22 |
CN105008764B (en) | 2018-04-20 |
JP6154162B2 (en) | 2017-06-28 |
US9903442B2 (en) | 2018-02-27 |
JP2014173663A (en) | 2014-09-22 |
TW201446406A (en) | 2014-12-16 |
WO2014136638A1 (en) | 2014-09-12 |
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